Mastering JavaScript Functional Programming

Arrow functions

Arrow functions are just a shorter, more succinct way of creating an (unnamed) function. Arrow functions can be used almost everywhere a classical function can be used, except that they cannot be used as constructors. The syntax is either (parameter, anotherparameter, ...etc) => { statements } or (parameter, anotherparameter, ...etc) => expression. The first one allows you to write as much code as you want; the second is short for { return expression }. We could rewrite our earlier Ajax example as:

$.get("some/url", data, (result, status) => {    // check status, and do something    // with the result});

A new version of the factorial code could be:

const fact2 = n => {    if (n === 0) {        return 1;    } else { return n * fact2(n - 1); ...